Man-made obstructions across rivers and streams present constant and serious impediments to the natural migrations of fish. In particular, many fish of certain species, e.g., striped bass and eels, are frequently denied access to their traditional spawning grounds by such obstructions. As a result, their numbers have been rapidly declining. Various attempts have been made to alleviate the situation. Fishways are common devices to help solve the problem.
As an adolescent, in the early 1940's, living along a small Pennsylvania stream, I frequently constructed small dams across the stream to create a "swimming hole" until a foul storm would quickly demolish my efforts. However, during the short time between storms when the little dam was functioning, I devised a way to permit the fish (especially, trout) to ford the obstruction. (My father warned me about the legal problems of obstructing a stream, wasting time and creating a nuisance-) Having built the dam across the stream with sand bags and rocks and put in a over-flow pipe, I realized the fish could not navigate the strong stream of water up and through the pipe. In order to by-pass the problem, I dug a small trench on the same level of the stream bed along the bank extending from the dam to the "fresh water" above the lake area. The trench then opened into the "fresh water" of the stream. At the dam site, I used another discarded piece of terracotta pipe which I sand-bagged in the trench. Then I continued the trench down stream into the normal flow of water. Since the dam was never more than three or four feet high and about twenty-five feet long, the by-pass system was not a major inconvenience. However, I had the satisfaction of watching the trout and minnows swim up and down the by-pass. I also had the good fortune of placating my parents until another chore in the field demanded my attention-
The intervening years since adolescence have been far removed from the days of building swimming holes. However, it was by chance that I heard on the radio a few months ago that Virginia was interested in replenishing its striped bass species. But, the many dams and obstructions on the rivers and streams prevented migration of the fish to their traditional spawning grounds. It was a reminder of my parents' admonition and my youthful attempts to have a legal swimming hole that spurred me to answer the call of the Virginia dilemma.
Field Search: Prior articles on patents of interest are particularly exemplified by U.S. Pat. No. 1,569,419 (Chase) and include U.S. Pat. Nos. 1,798,238 (Wass), 3,269,124 (Leathers), 3,772,891 (Raistakka) and 4,260,286 (Buchann).